Alert archive / Texas / Flash Flood Warnings in 2021

Flash Flood Warning 9, NWS Houston/Galveston, TX

May 17, 2021Liberty County, Texas

NWS Houston/Galveston, TX issued this flash flood warning at May 17, 2021, 2:06 PM CDT for Liberty County, Texas. It was in force for 3 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
May 17, 2021, 2:06 PM CDT (19:06 UTC)
Expired
May 17, 2021, 5:15 PM CDT
In force
3 hr
Issued by
NWS Houston/Galveston, TX
Area
Storm-based polygon
Flood severity
None

County Liberty County, TX

The radar

The Houston radar (KHGX), 84 km from the middle of the area, began a volume at 19:09 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

TimeReportWhereRemark
May 17, 2:18 PM CDTFLASH FLOOD2 Ssw Daisetta, TXCOUNTY ROAD 2017 SOUTH OF DAISETTA IS FLOODED.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 7.1 hours before the alert went out and 144 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Lake Charles Mun, LA at 12:00Z on 2021-05-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 626 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lake Charles Mun, LA at 12:00Z on 2021-05-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 207 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
626 J/kg
Mixed-layer CIN
-14 J/kg
Mixed-layer LCL
699 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
207 m²/s²
0-3 km storm-relative helicity
314 m²/s²
Significant tornado parameter
0.7
Supercell composite
10.3

Open this sounding in Storm Lab

The text

As transmitted.

014 
WGUS54 KHGX 171906
FFWHGX
TXC291-172215-
/O.NEW.KHGX.FF.W.0009.210517T1906Z-210517T2215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Houston/Galveston TX
206 PM CDT Mon May 17 2021

The National Weather Service in League City has issued a

* Flash Flood Warning for...
  Central Liberty County in southeastern Texas...

* Until 515 PM CDT.

* At 206 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 3 and 6 inches of rain 
  have fallen. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Doppler radar.

  IMPACT...Flooding of small creeks and streams, urban areas,
           highways, streets and underpasses as well as other
           drainage and low lying areas.

* Some locations that will experience flash flooding include...
  Northeastern Liberty, Ames, Daisetta, Hardin, Plum Grove, 
  Kenefick, Devers, Dayton Lakes and Moss Hill.

Additional rainfall amounts of 1 to 3 inches are possible in the 
warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Excessive run off from heavy rainfall will cause flooding of small 
creeks and streams, country roads, farmland, and other low lying 
spots.

Stay away or be swept away. River banks and culverts can become 
unstable and unsafe.

&&

LAT...LON 3011 9451 3010 9450 3001 9458 3004 9473
      3016 9507 3019 9509 3031 9505 3034 9482
      3020 9463 3017 9462 3015 9461 3014 9461
      3011 9460 3011 9452

FLASH FLOOD...RADAR INDICATED

$$

CR
1 follow-up statement
627 
WGUS74 KHGX 172211
FFSHGX

Flash Flood Statement
National Weather Service Houston/Galveston TX
511 PM CDT Mon May 17 2021

TXC291-172221-
/O.EXP.KHGX.FF.W.0009.000000T0000Z-210517T2215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Liberty TX-
511 PM CDT Mon May 17 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 515 PM CDT THIS AFTERNOON FOR 
CENTRAL LIBERTY COUNTY...

The heavy rain has ended, although light to moderate rain will 
continue through the next couple of hours. Please continue to heed 
remaining road closures.

A Flash Flood Watch remains in effect until 700 AM CDT Thursday for 
portions of south central Texas and southeast Texas.

LAT...LON 3011 9451 3010 9450 3001 9458 3004 9473
      3016 9507 3019 9509 3031 9505 3034 9482
      3020 9463 3017 9462 3015 9461 3014 9461
      3011 9460 3011 9452

$$

The office that day

Everything else NWS Houston/Galveston, TX issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 16, 7:56 PM CDTSpecial Marine WarningHGX34 min
May 16, 8:27 PM CDTRiver Flood WarningHGXJackson11 hr
May 16, 8:42 PM CDTSpecial Marine WarningHGX48 min
May 16, 10:16 PM CDTSpecial Marine WarningHGX44 min
May 16, 11:11 PM CDTSpecial Marine WarningHGX64 min
May 17, 1:16 AM CDTSpecial Marine WarningHGX89 min
May 17, 2:45 AM CDTSpecial Marine WarningHGX45 min
May 17, 12:57 PM CDTAreal Flood AdvisoryHGXLiberty2 hr
May 17, 1:41 PM CDTFlash Flood WatchHGXAustin, Brazoria, Brazos, Burleson, Chambers, Colorado and 17 more68 hr
May 17, 2:08 PM CDTSpecial Weather StatementHGXSan Jacinto52 min
May 17, 2:09 PM CDTAreal Flood AdvisoryHGXGrimes, Montgomery, San Jacinto, Walker, Waller, Washington3 hr
May 17, 2:44 PM CDTSpecial Weather StatementHGXLiberty, Montgomery46 min
May 17, 2:59 PM CDTAreal Flood AdvisoryHGXAustin, Colorado, Harris, Liberty, Montgomery, San Jacinto and 2 more3 hr
May 17, 3:13 PM CDTAreal Flood AdvisoryHGXChambers, Harris, Liberty, Montgomery2 hr
May 17, 3:19 PM CDTSpecial Weather StatementHGXAustin, Colorado56 min
May 17, 3:21 PM CDTFlash Flood WarningHGXChambers, Harris, Liberty3 hr
May 17, 3:23 PM CDTSpecial Weather StatementHGXChambers, Harris67 min
May 17, 3:46 PM CDTSpecial Marine WarningHGX89 min
May 17, 4:08 PM CDTAreal Flood AdvisoryHGXHarris112 min
May 17, 4:25 PM CDTSpecial Weather StatementHGXAustin, Brazoria, Colorado, Fort Bend, Galveston, Harris and 1 more65 min
May 17, 5:02 PM CDTAreal Flood AdvisoryHGXBrazoria, Fort Bend, Galveston, Harris118 min
May 17, 5:07 PM CDTRiver Flood WarningHGXLiberty36 days
May 17, 5:15 PM CDTSpecial Marine WarningHGX45 min
May 17, 5:30 PM CDTSpecial Marine WarningHGX90 min
May 17, 5:37 PM CDTAreal Flood AdvisoryHGXAustin, Colorado, Fort Bend, Harris, Waller, Wharton113 min
May 17, 5:44 PM CDTSpecial Weather StatementHGXFort Bend61 min
May 17, 6:14 PM CDTAreal Flood AdvisoryHGXBrazoria, Fort Bend, Galveston, Harris, Matagorda, Wharton2 hr

Nearby

Flash Flood Warnings in Texas, 2021Every flash flood warning in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.